UChicago - Spintronics approach enables for a new quantum technologies

A research team, including members from the University of Chicago (UChicago) Institute for Molecular Engineering have managed to demonstrate the unique powers of quantum technologies. The research has been published in the Proceeding of the National Academy of Sciences(PNAS).

The technologies have been shown to exploit quantum mechanics. The physics of quantum mechanics has been known to dominate the atomic world, and its ability to perform different tasks, for example, nanoscale temperature measurements and processing quantum information with lasers.

The published research is concerned with the manipulation of the same material, that being an atomic-scale defect in diamond known as the Nitrogen (N2) vacancy centre. Such research has also been shown to leverage the intrinsic "spin" of this defect for use in temperature measurement and information processing applications.

As stated by David Awschalom, principle investigator (PI) on to the published research and a Liew Family Professor in Molecular Engineering - "these studies build on research efforts undertaken over the last 20 years to isolate and control single electronic spins in the solid state," - and - "much of the initial motivation for working in this field was driven by the desire to make new computing technologies based on the principles of quantum physics. In recent years the research focus has broadened as we've come to appreciate that these same principles could enable a new generation of nanoscale sensors."

Controlling qubits with light

In another PNAS paper, Awschalom and six co-authors from the University of California, Santa Barbara (UoC-SB) and the University of Konstanz (UoK) have described a technique that offers new routes towards the creation of quantum computers, which would possess more capability than modern classical computers.

In their publication, above, Awschalom's team developed protocols to fully control the quantum state of the defect with light instead of electronics. The quantum state of interest in this defect is its electronic spin, which acts as a quantum bit (qubit), which is the basic unit of a quantum computer. For example, in classical computers, bits of information exist in one of only two states: binary code zero (0) or one (1). However, in the quantum mechanical realm, objects can exist in multiple states at once, thus, enabling for complex processing.

As Awschalom states, because his research is an all-optical scheme for controlling qubits in semiconductors - "obviates the need to have microwave circuits or electronic networks," - and - "instead, everything can be done solely with photons, with light."

Because it is a fully optical method, it shows promise as a scalable approach to qubit control. Also, the scheme has been shown to be more versatile then conventional methods and could be used to explore quantum systems in a broad range of materials that might otherwise be difficult to develop as quantum devices.

Single spin thermometers

The quantum thermometer application, which was also published in PNAS, represents a new direction for the manipulation of quantum states, which is typically linked to computing, communications and encryption. In recent years, defect spins had also emerged as promising candidates for nanoscale sensing of magnetic and electric fields at room temperature (RT). Since thermometry is now added on to the list, Awschalom foresees the possibility of developing a multi-functional probe based on quantum physics.

Awschalom states - "with the same sensor you could measure magnetic fields, electric fields and now temperature, all with the same probe in the same place at approximately the same time," - and - "perhaps most importantly, since the sensor is an atomic-scale defect that could be contained within nanometer-scale particles of diamond, you can imagine using this system as a thermometer in challenging environments such as living cells or microfluidic circuits."

A graduate student in physics at UoC-SB and a lead author of the temperature sensing work, David Toyli, stated that a key aspect of the innovation has been the development of control techniques for manipulating the spin that make it a much more sensitive probe for temperature shifts - "we've been exploring the potential of defect spins for thermometry for the past few years," - and - "this latest work is exciting because we've succeeded in adapting techniques used for stabilising quantum information to measuring temperature-dependent changes in the quantum states. These techniques minimise the effects of environmental noise and allow us to make much more sensitive temperature measurements."

It is claimed by Awschalom that the chemical properties of a diamond-based thermometer can also support the idea that the system could be useful for measuring temperature gradients in biological systems, such as the interior of living cells. However, the initial studies suggest that the method is flexible and probably lends itself to applications not yet realised - "like any new technology development, the exciting thing is what people will do with this now." Original article available here

As with similar type of quantum dot/technology studies its future potential has been handsomely sold. However, as stated previously, DCN Corp strongly believes it can compete by providing a cost-effective and efficient nano-fabrication process. Going forward, if you and/or your colleagues are interested in making DCN Corp's alternative process reality - please ensure to contact the company as soon as practicably possible.